%heading {
    text-transform: uppercase;
    font-weight: bold;
}   

.heading-primary {
    @extend %heading;
    @include font-size(3);
}

.heading-secondary {
    @extend %heading;
    @include font-size(2);
}

.heading-tertiary {
    @extend %heading;
    @include font-size(1.5);
}